Probed collections

This project is part of the Pyrustic Open Ecosystem.

Installation . Latest . Documentation

Overview

Sometimes you need to know when the content of a data collection has changed.

Probed is a library that exposes three classes: ProbedDict, ProbedList and ProbedSet.

These classes are containers like the built-in Python containers (dict, list, set) which they subclass but with not a twist but two twists:

• be notified when the content of your data collection changes (if you wish to be notified);
• being able to put a probe into data collection to do more than just be notified.

Let's write a script to see Probed in action:

# script.py
from probed import ProbedList


def on_change(context):
    msg = "\nThe {} operation changed the {} collection\n{}"
    print(msg.format(context.operation, context.container, context.collection))


plist = ProbedList(on_change=on_change)
plist.append("hi")
plist.insert(1, "friend")

Let's run the script:

$ python3 script.py

The append operation changed the list collection
['hi']

The insert operation changed the list collection
['hi', 'friend']

Now, let's discover what the probe feature does and how to use it:

# script.py
from probed import ProbedSet


def probe(context):
    # this probe will lower strings added to the collection
    # also, the object None isn't allowed in the collection
    if context.operation == "add":
        if context.item is None:
            context = None
        else:
            context.item = context.item.lower()
    return context


pset = ProbedSet(probe=probe)
# add items
pset.add("RED")
pset.add(None)
pset.add("Green")
# print
print(pset)  # {'red', 'green'}

In the last script, the probe was used to control the items added to the data collection.

All operations that change the contents of the built-in containers are covered by probed.

Read the modules documentation !

Related project

The Shared data exchange and persistence library uses Probed to implement the autosave feature !

Discover Shared !

Installation

Probed is cross platform and versions under 1.0.0 will be considered Beta at best. It is built on Ubuntu with Python 3.8 and should work on Python 3.5 or newer.

For the first time

$ pip install probed

Upgrade

$ pip install probed --upgrade --upgrade-strategy eager

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